Good point, and I agree. Sunk cost fallacy and all that. I wouldn't consider those "objective", but I don't think it's worth arguing over the definition of that word when I think we otherwise agree.

I also would agree that sometimes time has been wasted creating too many tests. Perhaps that time could have been spent to greater effect.

I also think that even if, in retrospec, a test is very tightly coupled and specific to one implementation, that test still might have revealed bugs and may have helped the original author. If that test is now a burden, throw it away.